The positive regulator of gene expression specified by the bacteriophage lambda Q gene is proposed to work by counteracting a transcriptional termination event. We intend to test this hypothesis and determine the detailed mechanism of action of this regulator by purifying it and investigating its activity in a purified system with defined components. We also will seek evidence for the antitermination mechanism in late gene control and also in control of phage repressor synthesis by a) attempting to detect the RNA postulated to result from transciption through the terminator and b) examining the occurrence and origin of the small molecular weight in vitro transcripts that provide part of the primary evidence that termination controls exist in these systems. BIBLIOGRAPHIC REFERENCES: Roberts, J.W., & C.W. Roberts. 1975. "Proteolytic Cleavage of Bacteriophage Lambda Repressor in Induction". Proc. Nat. Acad. Sci. 72, 147. Roberts, J.W. 1975. "Transcription Termination and Late Control in Phage Lambda". Proc. Nat. Acad. Sci. 72, 3300.